Global City Populations

Map Projection

Photo by Steven Diaz on Unsplash

Seaside Top: World Trade Center Tokyo Observation Deck, Minato Ku, Japan

Any city, however small, is in fact divided into two.
One the city of the poor, the other of the rich.
These are at war with one another…
— Plato

Ingest

world cities with coordinates and population

world_cities <- read.csv("archetypes/capital-cities-population/world-cities.csv", header = TRUE, encoding = "UTF-8")
world_cities <- filter(world_cities, population > 0 )
world_cities

Load Map

Natural Earth

ne_world <- ne_countries(scale = "small", returnclass = "sf")
ne_world <- filter(ne_world, iso_a3 != "ATA")

Set crs

for map and data set

ne_world <- ne_world %>% st_as_sf() %>% st_set_crs(4326)

world_cities_sf <- world_cities %>% st_as_sf(coords = c("lng", "lat"), crs = 4326)

Plot

showing map and data projected as Tissot

# theme parameters
theme_opts <- theme(
  legend.position = "bottom",
  legend.title = element_blank(),
  axis.text = element_blank(),
  #axis.line = element_blank(),
  #axis.ticks = element_blank(),
  axis.title = element_blank(),
  #panel.grid = element_blank(),
  #panel.grid.major = element_blank(),
  #panel.grid.minor = element_blank(),
  panel.background = element_blank(),
  panel.border = element_blank(),
  plot.background = element_blank(),
)

v1 = ggplot() +
  geom_sf(data = ne_world, color="#AAAAAA", fill="#FFFFFF", size=0.5) +
  geom_sf(data = world_cities_sf, aes(size = population, alpha = population), color="#C2185B") +
  #scale_x_continuous(name = NULL, breaks = seq(-120, 120, by = 60)) +
  #scale_y_continuous(name = NULL, breaks = seq(-60, 60, by = 30)) +
  scale_size_continuous(name = "",
                        range = c(0.5, 10), 
                        breaks = c(1000000, 5000000, 10000000, 30000000),
                        labels = c("1M", "5M", "10M", "30M")) +
  scale_alpha_continuous(range = c(0.1, 0.6), guide = "none") +
  coord_sf(crs = "+proj=tissot +lat_1=60 +lat_2=65") +
  theme_bw() +
  labs(x="", # Longitude
       y="", # Latitude
       title = "Global City Populations", 
       subtitle="Tissot Projection") +
  theme_opts

girafe(ggobj = v1, width_svg = 16, height_svg = 12,
       options = list(opts_sizing(rescale = TRUE, width = 1.0))
)

Plot

showing map and data projected as Murdoch I

v2 = ggplot() +
  geom_sf(data = ne_world, color="#AAAAAA", fill="#FFFFFF", size=0.5) +
  geom_sf(data = world_cities_sf, aes(size = population, alpha = population), color="#C2185B") +
  #scale_x_continuous(name = NULL, breaks = seq(-120, 120, by = 60)) +
  #scale_y_continuous(name = NULL, breaks = seq(-60, 60, by = 30)) +
  scale_size_continuous(name = "",
                        range = c(0.5, 10), 
                        breaks = c(1000000, 5000000, 10000000, 30000000),
                        labels = c("1M", "5M", "10M", "30M")) +
  scale_alpha_continuous(range = c(0.1, 0.6), guide = "none") +
  coord_sf(crs = "+proj=murd1 +lat_1=30 +lat_2=50") +
  theme_bw() +
  labs(x="", # Longitude
       y="", # Latitude
       title = "Global City Populations", 
       subtitle="Murdoch I") +
  theme_opts

girafe(ggobj = v2, width_svg = 16, height_svg = 12,
       options = list(opts_sizing(rescale = TRUE, width = 1.0))
)

References

citations for narrative and data sources

Narrative: Proj.org, Projections, GO
Data: simplemaps, GO